Add docstring linting (D-class rules) to ruff configuration #212

Description

The project currently ignores all docstring linting rules (D-class) in the ruff configuration with a TODO comment.

Location

pyproject.toml:60

[tool.ruff.lint]
# The D (doc) and DTZ (datetime zone) lint classes current heavily violated - fix later
select = ["ALL"]
ignore = [
    "D",  # todo: docstring linting
    # ...
]

Impact

• Inconsistent or missing docstrings across the codebase
• Reduced code maintainability and readability
• Harder for new contributors to understand code functionality

Suggested Implementation

1. Start by enabling specific D-rules that are least violated (e.g., D100, D101 for missing docstrings)
2. Gradually fix existing violations or use per-file ignores for legacy code
3. Eventually enable all D-rules for new code

Related

Similar TODO exists for DTZ (datetime zone) rules which should also be addressed.